/*
 * Copyright (c) 2014, marco.tamburelli@gmail.com
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met: 
 * 
 * 1. Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer. 
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution. 
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package org.omorphdb.core.storage.document;

import java.io.IOException;
import java.util.ArrayList;

import org.omorphdb.core.index.ChainedIndex;
import org.omorphdb.core.index.IndexType;
import org.omorphdb.core.index.Indexes;
import org.omorphdb.core.value.Value;
import org.omorphdb.core.value.ValueType;

/**
 * Represents a field bound to a chained index. When the filed is updated and
 * the parent document saved, the index should be updated as well.
 * 
 * @author Marco Tamburelli
 * 
 * @param <T>
 */
public class ChainedIndexField<T> extends BaseField<T>
{
	protected Value<T> oldValue;

	protected final ValueType type;
	protected final DocumentDescriptor docDescr;

	protected ArrayList<ChainedIndex<T>> indexes;

	public ChainedIndexField(DocumentDescriptor docDescr, String name, ValueType type, IndexType[] indexTypes,
			Indexes indexes) throws IOException
	{
		super(name);

		this.docDescr = docDescr;
		this.type = type;

		this.indexes = new ArrayList<>(indexTypes.length);

		for (int i = 0; i < indexTypes.length; i++)
		{
			ChainedIndex<T> index = indexes.getIndex(this.docDescr.getClassID(), super.name, this.type, indexTypes[i]);
			if (index != null) this.indexes.add(index);
		}
	}

	@Override
	public void setValue(Value<T> value, boolean updateAware)
	{
		if (updateAware) this.value = value;
		else this.oldValue = this.value = value;
	}

	@Override
	public void doAfterSave() throws IOException
	{
		/*
		 * This method should be fired when a document has been saved, so its
		 * position changes. It follows that if this document was registered
		 * with a not null value, it should be unregistered.
		 */
		if (this.oldValue != null) for (ChainedIndex<T> index : this.indexes)
			index.unregister(this.oldValue.get(), this.docDescr.getDocumentPosition());

		/*
		 * In case the provided value is not null, it means that the document
		 * should be registered.
		 */
		if (super.value != null) for (ChainedIndex<T> index : this.indexes)
			index.register(super.value.get(), this.docDescr.getDocumentPosition());
	}
}
